Method of manufacturing semiconductor device

Abstract

A problem of a resist mask collapse due to a plasma process is solved. In a method of manufacturing a semiconductor device including steps of a plasma process to a sample having a mask made of an organic material, the plasma process includes a first step of a plasma process under a gas containing any of fluorine, oxygen, or nitrogen, or containing all of them, and a second step of the plasma process under a gas containing a rare gas without containing any of fluorine, oxygen, and nitrogen, and the first step and the second step are repeated.

What is claimed is: 
     
       1. A method of manufacturing a semiconductor device comprising steps of a plasma process performed on a semiconductor substrate having an insulating film and a mask formed on the insulating film and made of an organic material,
 the plasma process comprising:
 a first step of generating a stress to an organic material comprising a first photoresist film and an antireflection film so as to form a second photoresist film and a patterned antireflection film, said second photoresist film and patterned antireflection film having a second pattern shrinking the first pattern using a gas containing a rare gas without containing any of fluorine, oxygen, and nitrogen; 
 a second step of relaxing the stress from the second photoresist film and the patterned antireflection film using a gas containing a rare gas without containing any of fluorine, oxygen, and nitrogen; and 
 etching the insulating film using the second photoresist film and the patterned antireflection film as a mask, 
 
 wherein the first step and the second step are alternately repeated, and 
 wherein the first step is a performed for a time of 2 seconds or longer and 15 seconds or shorter. 
 
     
     
       2. The method of manufacturing the semiconductor device according to  claim 1 , wherein
 a last step of the plasma process is the second step. 
 
     
     
       3. The method of manufacturing the semiconductor device according to  claim 1 , wherein
 an aspect ratio (height/width) of the mask is 2 or larger, and 
 a pattern dimension is 100 nm or smaller. 
 
     
     
       4. A method of manufacturing a semiconductor device comprising:
 preparing a semiconductor substrate having an insulating film formed over the semiconductor substrate, an antireflection film made of an organic material and formed on the insulating film, and a first photoresist film having a first pattern on the antireflection film; 
 performing a first plasma step on the first photoresist film and the antireflection film so as to form a second photoresist film and a patterned antireflection film, said second photoresist film and patterned antireflection film having a second pattern shrinking the first pattern using a gas containing a rare gas without containing any of fluorine, oxygen, and nitrogen; 
 performing a second plasma step on the second photoresist film and the patterned antireflection film to relax the stress from the second photoresist film and the patterned antireflection film using a gas containing a rare gas without containing any of fluorine, oxygen, and nitrogen; and 
 etching the insulating film using the second photoresist film and the patterned antireflection film as a mask, 
 wherein the first plasma step is performed for a time of 2 seconds or longer and 15 seconds or shorter. 
 
     
     
       5. The method of manufacturing a semiconductor device according to  claim 4 , further comprising repeating the first plasma step and the second plasma step in order to pattern the insulating film. 
     
     
       6. The method of manufacturing a semiconductor device according to  claim 4 , wherein the second plasma step is a last step of a plasma process. 
     
     
       7. The method of manufacturing a semiconductor device according to  claim 4 ,
 wherein an aspect ratio (height/width) of the mask is 2 or larger, and 
 wherein a pattern dimension is 100 nm or smaller. 
 
     
     
       8. The method of manufacturing a semiconductor device according to  claim 4 ,
 wherein said first plasma step and said second plasma step are performed in sequence so as to prevent deformation of said second photoresist organic film and said patterned antireflection organic film.